Free Shipping on all orders $35 and up.

We offer standard delivery in 3 business days or less.

Please see our shipping map below for estimated times.

Estimated standard delivery time to the U.S. and Puerto Rico

Delivery time estimates do not apply to large or heavy items that require special
shipping (including most TVs), items shipped directly from the manufacturer, or
out-of-stock items. Some items that ship from the manufacturer can only be delivered
to addresses within the 48 contiguous states.

Delivery time for standard shipping to any of the 50 U.S. states or Puerto Rico is 1-3 business days. Saturday, Sunday and national holidays are not considered business days for delivery purposes.

Ask an expert advisor

Polk Audio's Mobile Monitor Series subwoofers bring out superior performance from lighter materials, so you'll get the impact you want without the extra weight of a conventional system. Advanced engineering and optimized components reproduce your sound with uncompromising accuracy, for low end that is rich and clear.

What's a component sub and why would I want one?

A component sub is simply a speaker that's designed to reproduce bass once it's installed in a compatible enclosure. Think about the impact of a movie soundtrack in a big theater or even in your own home HDTV setup. A component sub can add the same kind of power to the music in your car. And a car sub is not all about the boom that you hear on a street corner (although that's cool too) - you can pair a component sub with your choice of enclosure to get bass just the way you like it, from tight and punchy to fat and loose. And once you experience music in your car with a well-tuned subwoofer, you'll never go back.

Product Research

Features

Klippel Optimized: Using a state-of-the-art Klippel Distortion
Analyzer, Polk engineers were able to optimize the woofer's motor structure, voice
coil alignment and suspension for the best possible performance, even at extreme
listening levels.

Polymer Woofer Cone with Butyl Rubber Surrounds: The Polymer
Woofer Cones and Butyl Rubber Surrounds will not break down over time and will
survive the rigors of harsh automotive environments.

High Temperature Copper Voice Coil (50mm) and Polyamide Former:
High Temperature 50mm Copper Voice Coil and Polyamide Former withstand the most
rigorous use while maintaining extremely low distortion for bass punch and output.

Carbon Composite Basket: The woofer's carbon composite basket is
lightweight and will not flex during music audio peaks.

Preconditioning Period: Mobile Monitor subwoofers will achieve
even greater performance once they are thoroughly broken in. To break in your new
MM subwoofer, play 20 to 30 hours of music at moderate levels.

Marine Certified Woofer: Polk MM Series speakers are built to
withstand exposure to moisture and UV rays, so they work well in boats and cars.
They also include stainless mounting hardware for corrosion and rust resistance.

Enclosure Compatibility

Recommended Sealed Box Volume: Polk recommends mounting this
woofer in a sealed enclosure made out of 3/4" MDF with an internal volume of
0.88 cu/ft.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to
find elsewhere. That's because we have our own in-house Product Research
team. They verify what’s in the box, check the owner's manual, and record
dimensions, features and specs. We stay on top of new products and technologies
to help people make informed choices.

* Agree to Terms
By checking this box you agree your review becomes the property of Crutchfield,
that you are over 18 years of age, that you own or have owned this product, and
that you are located within the United States or its territories. Please see our
Review Guidelines for more information. We reserve the right (but are not
obligated to) review all submissions and edit or remove any review in any manner
which we deem necessary. Your review should be posted within seven days.

great product

Written By Doug, michigan on Friday, December 26, 2014

"Coolness Factor"

Build Quality

Ease of Use

Sound Quality

Value

I've had this speaker for over a year now and it is by far the best speaker I have ever owned. I stuffed it behind the seat of my 97 crew cab powerstroke in a sealed box matched up with a polk amp and it packs a big punch without giving up any space in the cab. A+++

THIS SUB IS WORTH IT

i have a ford explorer with the third row and two kids who love sitting in the third row. before i had a 12w6v2 that took up the space for the third row. long story short i got rid of it.now i needed something small to go behind the third row. i have purchased polk compnent speakers before with great satisfaction, so i decided to go with there shallow sub. WOW i am very satisfied. i am powering my system with a pdx5 with 300 watts going to the sub. with sensitivity of the sub hight the 300 watts pouds very well. i am a polk fan for life:)

sounds good

Written By manju, goa, India on Sunday, August 14, 2011

hi, I have installed this sub in my Toyota Innova, it is powered by a JVC 2ch amp for a while with just 130 RMS and believe me even with such a small amp it sounds great. Hope it will further improve with Jbl GTO 1004 (320 RMS). Please don't go on its size and weight hear it to believe it. Cheers

Great SQ with a Hint of Punch

I went from 2-12" Alpine Type-Rs to two of these MM1240s. I notice a lot "punch" in my system, while still delivering outstanding sound quality. I've not messed too much with Polk Audio or shallow-mount subs, but I decided to give them a shot and I'm a little more impressed than I thought I'd be. I haven't found time yet to make a specific box for these subs so I've been using a Sound Ordnance box. I'm pushing 375wmrs to each sub and I have to say they sound clear and don't distort at lower Hz. If you want to get a good deal on these subs it's best to buy these in the scratch and dent section and get the Square-Trade 2-year warranty. Good luck and enjoy!

Excellent Sub

Written By Jake R, Oswego, NY on Tuesday, March 23, 2010

Space limtations on a 08 Chevy crew cab for enclosure size were frustrating, after talking with a Crutchfield advisor I decided to give the Polks a try. At first powered by an Alpine PDX600.1 i was impressed but wanted more, subs sounded good but not enough bump for my taste. Swapped out the amp for a PDX1000.1 and this is amazing. This convinced me to swap my PDX 100.4 to an PDX 150.4 for my four 6 3/4 Alpine type R components and this truck is down right amazing. Buy the Polk subs and power them big, you won't be disappointed.

Amazing Soud Quality and Sound Pressure Levels!

Written By Greenpeanut, Salt Lake City, UT on Thursday, January 07, 2010

I bought this sub to replace an Alpine Type R because although I liked it, I didn't feel I was getting the volume I wanted. After reading up on how sensitivity relates to power and sound output, I decided to try Polk Audio for the first time and was very impressed! This sub is rated truly at 92 db at 1 volt. Some other manufacturers pad this number by rating it at higher (Usually 2.83 volts) which usually increases the measurement by 4 to 5 db higher than the true number with 1 volt.

I have it set up with a sealed enclosure powered with a Rockford Fosgate P500.2 bridged with 500 watts. This sub hits a lot harder and cleaner than my Alpine Type R even when the volume levels are cranked. By the way the Type R has a sensitivity of 85 db. Although I know this number doesn't mean everything, just between these subs I can say I am very impressed with this sub! Awesome sound quality coupled with great SPL can't be beat, usually its only one or the other, but this has both! I will now recommend Polk Audio to anyone.

Also this sub is pretty shallow and fits in tight spaces like the trunk of my Acura Integra. Great sub!!!

great sub

Written By Eric, az. on Saturday, May 16, 2009

this a great sub. i have 2 of them running off an alpine mrp1000. that's 500 watts going to each of them. they do need about 20 to 30 hours to break in according to polk. its been about 3 weeks know and they are sound great. i have them in sealed enclosures w\ right about .88 to .90 airspace and and 1/2 pound of polly fill in each one which is ideal according to polk. which i would have say is spot on. i listen to all kinds of music and it all sounds good. i am also running mm6501 and mm651 in my car. i really like this polk mm line. i tried the db's and they just didn't sound right to me. crutchfield service is tops. car audio is kind of trial and error you have to put it in and try it and then be able to switch to something else if not satisfied. but know that i am with alpine electronics and polk mm speakers everything sounds awesome.

Impressed!!

Written By Adetokunbo, Clinton ,MS on Wednesday, April 01, 2009

I wanted a sub with a smaller box to replace my 12 inch JL AUDIO W3's in a
ported box all my other speakers in my car are POLK so I decided to give
them a try in a sealed box in a 2008 Nissan maxima. I tried Boston,Alpine,
and Kicker the bass didn't make it past the back seat. When polk says
sound quality they mean it two sealed polk 12's in a trunk sound way
better than my JL's and they are in a sealed box . JL is good but when it
comes to sealed sound quality polk cant be beat and when I turn it up I
BEAT THE BLOCK DOWN!! It hits hard when I want it too.

Hits hard and fits where others wont!

Written By Anthony, Long Beach, CA on Monday, January 26, 2009

I've had this sub for a while now and I love it. Not only does it sound great, but it's extremely shallow for a 12" sub. I own a single cab Dodge Dakota. For those of us single cab truck owners, it's hard to fit decent subs and amps into the cab. Well, I was able to fit this sub behind the seats with the correct box dimensions and still have room to move the seats all the way back. This is an awesome sub that sounds great, hits low, and fits where most subs wont. Definitely recommended (especially if you have a single cab truck).

Very nice sub

Written By Sam, Houston, TX on Sunday, August 10, 2008

I've had many sub's over the last 15 years or so. I have to admit that this
sub is hands down the best sub I've ever owned. Don't let the price scare
you. Its well worth the money. Anyways, the darned thing hits like no
other. I am hearing freq's that I've never heard before in some songs. I'm
pushing it with an Alpine MRP-F350 mono block amp. Great response and
no distortion whatsoever. I ran it through the paces when I had it finally
installed. I'm very impressed thus far.